Data center cooling

ABSTRACT

A modular data center, for housing and cooling electronic equipment, includes multiple housings, a first portion of the housings configured to hold heat-producing electronic equipment and a second portion of the housings configured to hold at least one cooling unit, each of the housings of the first portion having a front and a back and configured to hold the heat-producing electronic equipment such that gas is drawn into the equipment from fronts of the equipment, heated by the equipment to become heated gas, and expelled by the electronic equipment is expelled through the backs of the housings, where the housings are disposed and coupled to form a laterally-enclosed arrangement laterally enclosing a hot region and defining a top opening allowing gas to vertically exit the hot region, and where backs of the housings of the first portion are disposed adjacent to the hot region such that the heat-producing equipment, when mounted to the housings, will expel the heated gas into the hot region.

CROSS-REFERENCE TO RELATED ACTIONS

This application is a continuation of U.S. application Ser. No.10/863,740, filed Jun. 7, 2004 now U.S. Pat No. 7,046,514 and entitled,“Data Center Cooling,” which is a continuation-in-part of U.S.application Ser. No. 10/391,971, filed Mar. 19, 2003 now U.S. Pat. No.6,859,366 and bearing the same title.

FIELD OF THE INVENTION

Embodiments of the present invention are directed to cooling ofrack-mounted devices, and more particularly to a data centerinfrastructure having a cooling system.

BACKGROUND OF THE INVENTION

Communications and information technology equipment is commonly designedfor mounting to racks and for housing within enclosures. Equipment racksand enclosures are used to contain and to arrange communications andinformation technology equipment, such as servers, CPUs, internetworkingequipment and storage devices, in small wiring closets as well asequipment rooms and large data centers. An equipment rack can be an openconfiguration and can be housed within a rack enclosure. A standard racktypically includes front-mounting rails to which multiple units ofequipment, such as servers and CPUs, are mounted and stacked verticallywithin the rack. The equipment capacity of a standard rack relates tothe height of the mounting rails. The height is set at a standardincrement of 1.75 inches, which is expressed as “U” units or the “U”height capacity of a rack. A typical U height or value of a rack is 42U. A standard rack at any given time can be sparsely or denselypopulated with a variety of different components as well as withcomponents from different manufacturers.

Most rack-mounted communications and information technology equipmentconsumes electrical power and generates heat. Heat produced byrack-mounted equipment can have adverse effects on the performance,reliability and useful life of the equipment components. In particular,rack-mounted equipment housed within an enclosure is particularlyvulnerable to heat build-up and hot spots produced within the confinesof the enclosure during operation. The amount of heat generated by arack is dependent on the amount of electrical power drawn by equipmentin the rack during operation. Heat output of a rack can vary from a fewwatts per U unit of rack capacity up to 500 watts per U unit, or evenhigher, depending on the number and the type of components mounted tothe rack. Users of communications and information technology equipmentadd, remove, and rearrange rack-mounted components as their needs changeand new needs develop. The amount of heat a given rack or enclosure cangenerate, therefore, can vary considerably from a few tens of watts upto about 10,000 watts and beyond.

Rack-mounted equipment typically cools itself by drawing air along afront side or air inlet side of a rack or enclosure, drawing air throughits components, and subsequently exhausting air from a rear or vent sideof the rack or enclosure. Air flow requirements to provide sufficientair for cooling, thus, can vary considerably as a result of the numberand the type of rack-mounted components and the configurations of racksand enclosures.

Equipment rooms and data centers are typically equipped with an airconditioning or cooling system that supplies and circulates cool air torack-mounted equipment and enclosures. Many air conditioning or coolingsystems, such as the system disclosed in U.S. Pat. No. 6,494,050,require that an equipment room or data center have a raised floorconstruction to facilitate the system's air conditioning and circulationfunctions. These systems typically use open floor tiles and floor grillsor vents to deliver cool air from the air passageway disposed below theraised floor of an equipment room. Open floor tiles and floor grills orvents are typically located in front of equipment racks and enclosures,and along aisles between rows of racks and enclosures arrangedside-by-side.

The cooling systems and methods that require a raised floor constructiontypically do not efficiently meet the cooling requirements ofrack-mounted equipment. In particular, racks that include high-powerequipment having a thermal exhaust air output above 5,000 watts and upto 10,000 watts present a particular challenge for such systems andmethods. A raised floor construction typically provides an open floortile or a floor grill or vent having a venting area of about 12 by 12inches and is configured to deliver from about 200 cfm to about 500 cfmof cool air. A rack of high-power equipment drawing up to 10,000 wattsor more and requiring an air flow of approximately 1,600 cfm, therefore,would need about 3.2 to about 8 open floor tiles, grills or ventsdisposed around the rack's perimeter to supply sufficient cool air tomeet its cooling requirements. Such a floor configuration would bedifficult to achieve in equipment rooms crowded with racks andenclosures, and impossible to implement if racks and enclosures arearranged side-by-side in rows. Air cooling systems and methods thatincorporate raised floor configurations, thus, are typically only usedwith racks and enclosures spaced apart to provide sufficient floor areato accommodate multiple open floor tiles, grills or vents. For typicalrack spacing, this places a limit on the density of equipment that canbe achieved. When a raised floor is not used, the problem ofdistributing cool air from one or more centralized air conditioningsystems is even greater, as the cool air typically must be distributedacross a room containing rows of racks.

Equipment rooms and data centers are often reconfigured to meet newand/or different equipment needs that require individual racks andenclosures to be relocated and/or replaced. In this context, raisedfloor air cooling systems and methods are inflexible and can typicallyonly be reconfigured and/or retrofitted to service rearranged, relocatedand/or newly installed equipment racks at considerable cost. Raisedfloor configurations cannot easily and inexpensively accommodate themanner by which users typically deploy equipment racks and reconfigureequipment rooms and data centers to meet their new or changing needs.

In addition, cooling systems and methods that require raised floorconstruction lack physical flexibility and portability to operativelyaccount for a wide variation in electrical power consumption betweendifferent racks and enclosures in an equipment room, and, in particular,between racks and enclosures located in the same row. Cooling systemsand methods that rely upon raised floor air passageways and open floortiles, grills or vents to supply cool air cannot easily andinexpensively vary or concentrate cool air to those high power racksthat consume relatively large amounts of electrical power and have ahigh thermal air exhaust output. In addition, newly installed equipmentmay draw more electrical power than replaced or existing equipment tocreate thermal problem areas in functioning equipment rooms.

Further, a particular problem with existing air conditioning solutionsis that hot spots can develop in a room due to a lack of properrecirculation of exhaust air from racks to the return side of a room airconditioner. This can cause racks to undesirably draw warm air into theracks. To attempt to overcome air circulation problems, many room airconditioners are designed to provide very cool air of approximately 58degrees F. and receive return air having a typical temperature ofapproximately 78 degrees F. One problem with such air conditioners isthat with an output air temperature of 58 degrees F., and the latentcooling occurring to achieve this temperature, it is often necessary toadd a humidification system to increase moisture in the air in a datacenter. Such humidification systems can be expensive to install andoperate.

Therefore, it is desirable to provide a system and method for coolingrack-mounted communications and information technology equipment suchthat equipment cooling requirements are met efficiently andeconomically, both for data centers that have a raised floor and fordata centers that do not have a raised floor. A rack cooling system andmethod that is inexpensive, and able to support groups of particularlyhigh power racks and/or enclosures, or to overcome local thermal problemareas in an equipment room or data center is desirable.

SUMMARY OF THE INVENTION

A first aspect of the present invention is directed to a modular datacenter. The modular data center includes a plurality of racks, each ofthe racks having a front face and a back face, wherein the plurality ofracks is arranged in a first row and a second row, such that the backfaces of racks of the first row are facing the second row, and the backfaces of the racks of the second row are facing the first row. The datacenter also includes a first end panel coupled between a first rack ofthe first row and a first rack of the second row, the first end panelhaving a bottom edge and a top edge. Further, the data center includes asecond end panel coupled between a second rack of the first row and asecond rack of the second row, the second end panel having a top edgeand a bottom edge, and a roof panel is included to couple between thetop edge of the first panel and the top edge of the second panel.

The modular data center can be designed so that the roof panel iscoupled to a top portion of at least one rack of the first row and to atop portion of at least one rack of the second row, such that the roofpanel, the first end panel, the second end panel, and the first andsecond rows of racks form an enclosure around an area between the firstrow of racks and the second row of racks. The plurality of racks canfurther include cooling equipment that draws air from the area, coolsthe air and returns cooled air out of the front face of one of theracks. At least one of the first end panel and the second end panel caninclude a door. Further, at least a portion of the roof panel can betranslucent. The modular data center can have at least one rack thatincludes an uninterruptible power supply to provide uninterrupted powerto equipment in at least one other rack of the plurality of racks. Thefirst row of racks in the modular data center can be substantiallyparallel to the second row. In addition, the modular data center can bedesigned such that one of the plurality of racks includes coolingequipment that draws air from an area between the first row and thesecond row, cools the air and returns cooled air out of the front faceof one or more of the racks.

Another aspect of the present invention is directed to a method ofcooling electronic equipment contained in racks in a data center. Themethod includes arranging the racks in two rows, including a first rowand a second row that is substantially parallel to the first row, with aback face of at least one of the racks of the first row facing towards aback face of at least one of the racks of the second row. The methodalso includes forming an enclosure around an area between the first rowand the second row, and drawing air from the area into one of the racksand passing the air out of a front face of the one of the racks.

The method can include a further step of cooling the air drawn into theone of the racks prior to passing the air out of the front face. Thestep of forming an enclosure may include coupling first and second sidepanels and a roof panel between the first row and the second row. Atleast one of the first side panel and the second side panel may includea door and the roof panel can include a translucent portion.Additionally, the method can include using an uninterruptible powersupply to provide power to equipment in the racks.

Yet another aspect of the present invention is directed to a modulardata center that includes a plurality of racks, each of the racks havinga front face and a back face, wherein the plurality of racks is arrangedin a first row and a second row, such that the back faces of the racksof the first row are facing the second row, and the back faces of theracks of the second row are facing the first row. The modular datacenter further includes means for enclosing a first area between thefirst row and the second row, and means for drawing air from theenclosed area, cooling the air, and returning cooled air to a secondarea.

The means for drawing air can further include means for passing cooledair through the front face of one of the racks. The modular data centercan also be comprised of means for providing uninterruptible power toequipment in the racks. Access means for allowing access into the firstarea may also be a design feature of the modular data center.

Still another aspect of the invention is directed to a modular datacenter that includes a plurality of equipment racks, each of theequipment racks being configured to draw cooling air from a first areaand to provide exhaust air to a second area, and at least one enclosurepanel coupled between a first rack and a second rack of the plurality ofequipment racks. At least one of the equipment racks includes coolingequipment configured to draw exhaust air from the second area and toprovide cool air to the first area, and the plurality of equipment racksand the at least one enclosure panel are arranged to substantiallyenclose the second area.

The at least one enclosure panel can be a roof panel coupled from a roofof one equipment rack to a roof of another equipment rack. The datacenter can further include at least one end panel disposed between oneof the plurality of equipment racks and another one of the plurality ofequipment racks, the at least one end panel including a door thatprovides access from the first area to the second area. At least aportion of the roof panel can be translucent, and at least one of theplurality of equipment racks can include an uninterruptible powersupply.

Another aspect of the invention is directed to a method of coolingequipment in a plurality of equipment racks. The method includes drawingcooling air from a first area into at least one of the equipment racksand providing exhaust air from the at least one of the equipment racksinto a second area, providing an enclosure around the second area,drawing exhaust air from the second area into a second one of theplurality of equipment racks, cooling the exhaust air to produce cooledair, and providing the cooled air into the first area. The method canalso include arranging the plurality of equipment racks to form two rowswith the second area being between the rows.

In general, in another aspect, the invention provides a modular datacenter for housing and cooling electronic equipment, the data centerincluding multiple housings, a first portion of the housings configuredto hold heat-producing electronic equipment and a second portion of thehousings configured to hold at least one cooling unit, each of thehousings of the first portion having a front and a back and configuredto hold the heat-producing electronic equipment such that gas is drawninto the equipment from fronts of the equipment, heated by the equipmentto become heated gas, and vented by the electronic equipment through thebacks of the housings, and at least one panel coupled to a pair of thehousings to bridge a gap between the pair of the housings, where thehousings and the at least one panel are disposed and coupled to form alaterally-enclosed arrangement laterally enclosing a hot region anddefining a top opening allowing gas to vertically exit the hot region,and where backs of the housings of the first portion are disposedadjacent to the hot region such that the heat-producing equipment, whenmounted to the housings, will expel the heated gas into the hot region.

Implementations of the invention may include one or more of thefollowing features. The data center further includes the at least onecooling unit, the at least one cooling unit being configured to drawheated gas from the hot region into the at least one cooling unit, coolthe heated gas to become relatively cool gas, and to expel the heatedgas from the at least one cooling unit to a cool region that isseparated from the hot region the housings. The at least one coolingunit is configured to direct the cool gas toward fronts of the firstportion of the housings. The at least one cooling unit is configured todirect the cool gas toward bottom portions of the fronts of the firstportion of the housings. The at least one cooling unit is configured tocool the gas to, and expel the gas at, approximately 72° F. The datacenter further includes an uninterruptible power supply coupled to theat least one cooling unit and configured to provide backup power to theat least one cooling unit.

Implementations of the invention may also include one or more of thefollowing features. The at least one panel is a door configured to beopened to provide access to the hot region and to be closed to inhibithot gas from the hot region exiting the data center laterally from thehot region through the gap. The at least one panel is at leastapproximately a height of a shortest one of the first and secondportions of the housings. The plurality of housings are disposed in twoparallel rows, and wherein the at least one panel includes two doorsdisposed at opposite ends of the rows and coupling the two rows to eachother at the respective ends.

In general, in another aspect, the invention provides a system forcontaining and cooling electronic equipment that produces heat duringoperation, the system including multiple housings, a first portion ofthe housings being configured to allow gas to pass through fronts of thehousings, through interiors of the housings, and out through backs ofthe housings, the first portion of the housings being further configuredto contain the electronic equipment in an arrangement such that theequipment will draw gas through the fronts of the housings, through theequipment thereby heating the gas to produce heated gas, and expellingthe heated gas through the backs of the housings, the plurality ofhousings being disposed to form a substantial portion of a lateralenclosure laterally surrounding a hot region, closure means forlaterally coupling at least two of the housings to complete the lateralenclosure surrounding the hot region, the closure means and theplurality of housings providing a top opening such that the systemprovides substantially no upper bounds to the hot region, and coolingmeans, disposed in at least one of the housings, for cooling the heatedgas to produce the relatively cool gas and to provide a relatively coolgas to fronts of the first portion of the housings, where the pluralityof housings are disposed such that the electronic equipment, whileoperating, will expel the heated gas into the hot region.

Implementations of the invention may include one or more of thefollowing features. The cooling means is configured to direct therelatively cool gas toward bottom portions of the fronts of the firstportion of the housings. The cooling means is configured to cool theheated gas to approximately 72° F. to produce the relatively cool gas.The closure means includes at least one thermally-insulated doorconfigured to be opened to provide access to the hot region and closedto inhibit the heated gas from laterally exiting the hot region betweenthe housings to which the closure means is coupled. The housings aredisposed in two parallel rows, and wherein the closure means includestwo doors disposed at opposite ends of the rows and coupling the tworows to each other at the respective ends. The system further includesan uninterruptible power supply coupled to the cooling means andconfigured to provide backup power to the cooling means.

In general, in another aspect, the invention provides a method ofoperating and cooling rack-mounted electronic equipment, the methodincluding powering the rack-mounted electronic equipment to draw gasinto housings containing the equipment through fronts of the housings,heat the gas to produce heated gas, and expel the heated gas into a hotregion, inhibiting the heated gas from laterally exiting the hot region,except into a cooling mechanism, using the housings containing theequipment and at least one panel coupled to at least two of the housingswhile allowing the heated gas to upwardly exit the hot regionsubstantially unimpeded at least until the gas rises above tops of thehousings, drawing in at least some of the heated gas from the hot regioninto the cooling mechanism and cooling the drawn-in gas to produce coolgas, and providing the cool gas to fronts of the housings.

Implementations of the invention may include one or more of thefollowing features. The inhibiting includes injecting more heated gasinto the hot region and impeding lateral flow of the heated gas with atleast one barrier coupled between a gap between a pair of the housings.The providing includes directing the cool gas toward bottoms of thefronts of the housings.

The invention will be more fully understood after a review of thefollowing figures, detailed description and claims.

BRIEF DESCRIPTION OF THE FIGURES

For a better understanding of the present invention, reference is madeto the figures, which are incorporated herein by reference and in which:

FIG. 1 is a perspective view of a modular data center cooling system forrack-mounted equipment in accordance with one embodiment of theinvention;

FIG. 2 is a top view of another modular data system, similar to thesystem of FIG. 1;

FIG. 3 is a block flow diagram of a process of cooling equipment mountedin modular data centers in one embodiment of the invention;

FIG. 4 is a perspective view of a system including rack-mountedequipment and cooling units in accordance with the invention; and

FIG. 5 is a block flow diagram of a process of cooling equipment in thesystem shown in FIG. 4 using cooling units of the system shown in FIG.4.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention provide a data center infrastructure havinga cooling system for cooling rack-mounted electronic equipment.Embodiments of the invention provide a modular data center forrack-mounted equipment, wherein the modular data center provides powerdistribution, cooling and structural support for the rack-mountedequipment. The power distribution unit and cooling is provided in someembodiments using redundant systems to prevent downtime due toelectrical or mechanical failures. As understood by those skilled in theart, other embodiments are within the scope of the invention, such asembodiments used to provide infrastructure for equipment other thanelectronic equipment.

A system for providing power distribution for rack-mounted equipment,which can be used with embodiments of the present invention, isdescribed in U.S. patent application Ser. No. 10/038,106, entitled,“Adjustable Scalable Rack Power System and Method,” which is hereinincorporated by reference.

Referring to FIG. 1, a perspective view of a modular data center 10 isshown. The modular data center 10 includes a power distribution unit 14,a power protection unit 12, a floor mounted cooling unit 16, equipmentracks 18, and a hot room 22. The modular data center 10 also has a door52 having a window 54, a roof 56, a cooling water supply and return 60,and a voltage feed 58. The cooling water supply and return 60 canconsist of condenser water in the event that the cooling unit 16 is ofthe liquid cooled direct expansion variety, chilled water if coolingunit 16 is of the chilled water variety, or refrigerant supply andreturn if cooling unit 16 is of the air cooled direct expansion variety.The data center 10 is a modular unit comprised of the power distributionunit 14, the power protection unit 12 the floor mounted cooling unit 16,and equipment racks 18 positioned adjacent to each other to form a row32 and a row 34. Row 32 and row 34 are substantially parallel. The powerdistribution unit 14 and the power protection unit 12 can be locateddirectly adjacent to one another, and can be located at the end of oneof the rows. The floor-mounted cooling unit 16 may be located andpositioned adjacent to the power distribution unit 14. Remainingenclosures forming the at least one additional row in the data center 10are equipment racks 18. The hot room 22 is located between row 32 androw 34, and rows 32 and 34 comprise two of the perimeter walls of themodular data center 10.

The power distribution unit 14 typically contains a transformer, andpower distribution circuitry, such as circuit breakers, for distributingpower to each of the racks in the modular data center 10. The powerdistribution unit 14 provides redundant power to the racks 18 and canmonitor the total current draw. An uninterruptible power supply canprovide uninterruptible power to the power distribution unit 14.Preferably, the power distribution unit 14 includes a 40 kWuninterruptible power supply having N+1 redundancy, where the ability toadd another power module provides N+1 redundancy. In one embodiment ofthe invention, input power to the power distribution unit 14 is receivedthrough the top of the rack from a voltage feed 58. In one embodiment,the voltage feed 58 is a 240 volt feed (or 208 volt feed forthree-phase) coupled to the power distribution unit 14 that entersthrough the roof panel 56. Alternatively, the input power may bereceived from underneath the rack, as through a raised floor, or throughthe back of the rack.

The power protection unit 12 provides redundant power protection forcentralized information technology equipment, as is contained in theequipment racks 18. The power protection unit 12 can have individualpower modules and battery modules that can be individually added orremoved to accommodate different load requirements. The use of multiplepower modules and battery modules provides redundancy by allowingcontinued operation despite the failure of any one power module orbattery module. For example, the power protection unit can include aSymmetra PX® scalable, uninterruptible power supply having a three-phaseinput and a three-phase output, available from American Power ConversionCorporation, of West Kingston, R.I., or the power protection unit caninclude one of the uninterruptible power supplies described in U.S. Pat.No. 5,982,652, titled, “Method and Apparatus for ProvidingUninterruptible Power,” which is incorporated herein by reference.

The floor mounted cooling unit 16 provides heat removal by use of achilled water supply, which enters the unit through supply line 60.Alternatively, the cooling units can provide heat removal using DXcompressorized cooling via use of a direct expansion refrigerant-basedunit, which can be in the unit itself. The cooling unit may contain aprimary chilled water coil and secondary direct expansion coil withinthe same frame. The cooling unit can be configured for air, water orglycol use. Cooled air can be released through the bottom of the unit orthe top of the unit. In one embodiment of the invention, cool air isreleased from the cooling unit 16 out its front face, so that the airflow is from the back of the rack and out the front of the rack. Thecooling unit 16 can further be configured as one, two or three modules.In the embodiment shown in FIG. 1, a three-module cooling unit is used.

In the embodiment of FIG. 1, each of row 32 and row 34 is comprised ofsix racks. In embodiments of the invention, the number of racks and thefunction of the equipment in the racks can vary. In one embodiment ofthe invention, the racks 18 are modified standard 19 inch racks, such asthose available from American Power Conversion Corporation of WestKingston, R.I., under the trade name NETSHELTER VX Enclosures®.

The back face of each of the power distribution unit 14, the powerprotection unit 12, the floor mounted cooling unit 16, and the equipmentracks 18 faces the interior of the modular data center 10, or the hotroom 22. Essentially, the back faces of the racks in row 32 face theback faces of the racks in row 34. In one embodiment, the equipmentracks 18 have their rear doors removed so that each rack 18 remains opento the inside of the hot room 22. In the embodiment shown, the modulardata center 10 contains seven equipment racks 18. Alternatively, inanother embodiment, six equipment racks 18 complete the rows, but morethan seven equipment racks 18 can complete the rows contained in thedata center 10 and can be adjacent to one another or adjacent to otherenclosures in the data center 10, such as the power distribution unit14, the power protection unit 12, or the floor mounted cooling unit 16.

The door 52 located at the end of the row of racks is attached withhinges 53 to a detachable frame 55. The detachable frame 55 is locatedbehind the power protection unit 12. The detachable frame may bepositioned behind any one of the power protection unit 12, the powerdistribution unit 14, or the equipments racks 18, depending on which ofthe units are positioned at the end of a row in the data center 10. Thedetachable frame 55 allows the door 52 to be quickly removed forreplacement of the power protection unit 12 if necessary. The hot roomis accessible by the door 52 and can be monitored through theobservation window 54. Preferably, a door 52 is located at each end ofthe hot room 22. Generally, the door 52 is a 2×36 inch insulated,lockable steel door having an insulated observation window 54.

The water or refrigerant supply and return 60 can enter the hot roomthrough supply pipes into the roof 56 or directly into the roofs of theracks. The voltage feed 58 can also enter through the roof 56 or throughthe roofs of the racks. Alternatively, the water or refrigerant supplyand return 60 and the voltage feed 58 enter the hot room through araised floor on which the modular data center rests or from anotherlocation outside of the room and into the racks, such as into the sidesof the racks.

The roof panel 56 is preferably a semi-transparent plexiglass roof panelsupported by steel supports 62 that are positioned at intervals alongthe length 72 of the data center 10. The roof 56 extends to cover thetop of the hot room 22 located in the middle of the rows of racks. Theroof 56 can be easily detachable to allow for removal of racks 18 or thepower protection unit 12 when necessary. A roof panel 56 constructed ofsemi-transparent plexiglass allows room light to enter the spacedefining the hot room 22. Additionally, the plexiglass roof 56 ispreferably substantially airtight.

The hot room 22 is completely enclosed and has walls formed by thebackside of the racks 18 and walls comprised of the door 52 attached ateach end of the hot room 22. Alternatively, panels without doors can bethe walls that complete the hot room. The hot room 22 is a substantiallyairtight passageway when the roof panel 56 is in place. Thus, themodular data center 10 is an enclosed computer infrastructure defined onits outside perimeter by the front face of each of the racks 18, powerprotection unit 12, power distribution unit 14, and cooling unit 16, andhaving a hot room 22 in its midsection. The outside walls of the hotroom formed by the doors 52 are a portion of two of the outside walls ofthe modular data center 10.

Referring to FIG. 2, a top view of a modular data center 10 in oneembodiment of the invention is shown. The modular data center of FIG. 2is similar to that of FIG. 1, but has five racks in each of row 32 androw 34, rather than the six racks in each row of FIG. 1. With likenumbers referring to like embodiments, the modular data center 10 ofFIG. 2 is comprised of the power distribution unit 14, the powerprotection unit 12, the floor mounted cooling unit 16, the equipmentracks 18, and the hot room 22. The power protection unit 12 ispositioned directly adjacent to one side of the power distribution unit14, while a floor-mounted cooling unit 16 is positioned on the otherside of the power distribution unit. A service clearance area 20surrounds the modular data center 10. In FIG. 2, an embodiment of theinvention is shown having six equipment racks 18 and a cooling unit 16having two modules.

The dimensions of the modular data center 10 depend on the number ofracks included in each of the rows of racks. For example, a data center10 having six equipment racks 18 can have a width of 120″, indicated byarrow 28, a length of 120″, indicated by arrow 29, and a hot room width(row separation) of 36″, indicated by arrow 24, and a service clearance26 of preferably 36″ in width. With the inclusion of the serviceclearance 26, the floor surface area for the data center 10 is,preferably, a length 30 of 192″ and a width 31 of 192″. Alternatively,and referring again to FIG. 1, a data center 10 having seven equipmentracks 18 can have a width of 120″ and a length of 144″. With theinclusion of the service clearance 26, the floor surface area for analternate data center is 192″ by 216″. The dimensions of the modulardata center are given only as examples, but can vary significantlydepending upon the type and size of racks used to design the datacenter.

The modular data center 10 is operational when provided with a source ofchilled water, condensor water or refrigerant piping 60 and a voltagefeed 58. The data center can include a number of different power inputdesigns, but is preferably a 40 kW design, allowing 6.7 kW/rack in asystem having six equipment racks 18, or 5.7 kW/rack in a system havingseven equipment racks 18, for example. Cooling water or refrigerantenters the floor mounted cooling units 16 via supply lines 60. A commonsupply line 60 can provide cooling water to one or more cooling unitssimultaneously, as the cooling units 16 are connected to the commonsupply 60 with flexible hose that is easily disconnected.

The modular data center 10 provides cooling for equipment in the datacenter as follows. Air from the room, or ambient air, filters throughthe front of the racks 18 to cool the equipment stored in the racks 18.Air enters through the front of the racks 18 and is expelled out of thebackside of the racks 18. As the air passes through the equipment racks18, the temperature of the air rises. The respectively warmer air isexpelled into the hot room 22. The hot room 22 contains the warm air andprevents the warm air from mixing with air in the surrounding room. Thecooling unit 16 draws warm air from the hot room and returns cool air tothe room outside the data center 10. The warm air enters the coolingunits 16 directly from the hot room 22. The cooling unit acts to lowerthe temperature of the air, and the cooled air is then released into thesurrounding area. The air is recycled to the surrounding room at asubstantially cooled temperature. For example, the cooling unit 16generally receives air from the hot room at 95° F. and cools it to atemperature of approximately 72° F. before it is released into the areasurrounding the data center 10. The floor mounted cooling unit 16operates at substantially higher supply and return temperatures,allowing realization of high capacity without latent heat removal.

Referring to FIG. 3, with further reference to FIGS. 1–2, the datacenter 10 is configured to perform a process of cooling equipment storedin enclosed racks using an infrastructure having independent power andcoolant supplies. The process 100 includes the stages shown, althoughthe process 100 may be altered, e.g., by having stages added, deleted,or moved relative to the stages shown.

The process 100 of FIG. 3 includes stage 102, wherein power is suppliedfrom a power distribution unit to a plurality of equipment racks 18. Theequipment racks 18 may contain a variety of electronic equipment thatrequires a consistent power supply to avoid system downtime. Power issupplied via the voltage feed 58 that is connected to the powerdistribution unit 14, with the power protection unit 12 being preferablydisposed adjacent to the power distribution unit 14 to ensure redundantpower supply.

At stage 104, the racks 18 draw cool air from the surrounding roomthrough the front face of the racks 18. There may, for example, be anair distribution unit within the racks and/or within equipment containedin the racks that draws the room air into the rack 18 and distributesthe air throughout the rack to cool components contained in the rack. Asthe air passes through the rack 18, the air increases in temperature.

At stage 106, the racks 18 expel the air at an increased temperatureinto the hot room 22. The air is expelled out of the backside of theracks 18. As described above, in one embodiment, the racks 18 do nothave rear doors. In other embodiments, rear doors may be included on theracks with the warm air being expelled into the hot room through ventsin the doors. Air is held in the hot room 22 at an increased temperatureand mixing of the warm air with the surrounding ambient air isprevented. In one embodiment of the invention, the modular data centeris designed to maintain an air pressure in the hot room that isapproximately equal to the air pressure outside the hot room. Thisallows one of the doors to be opened without allowing cool air to enterthe hot room. In one such embodiment, the cooling unit provides 160cfm/kW.

At stage 108, the cooling unit draws the warm air from the hot room 22.The cooling unit 16 uses the cold water from the cold water supply 60 tocool the air from the hot room. At stage 110, the cooled air is releasedfrom the cooling unit into the surrounding room, which completes thecooling cycle. The air in the surrounding room is then drawn into theracks 18 once again, and the cycle continues.

Other embodiments are within the scope and spirit of the appendedclaims. For example, air could be forced up through the equipment racks18. Air moved through the racks 18 could be of varying temperatures,including hot air. The data center 10 may be configured to distributegases other than air. Additionally, a refrigerant or other coolant maybe used rather than cold water. Further, a controller can be coupled tothe data center 10 to monitor air temperatures and flow rates, as wellas power supply so that each rack is provided adequate powerconsistently. A data center may contain a single equipment rack 18having a single cooling unit 16 creating an individual data center,whereby power is distributed to a single data center 10 or multiplesingle-rack data centers simultaneously.

In one embodiment of the present invention, one or more cooling unitsare centrally located in the modular data center to try to equalize thedraw of hot air from each of the racks into the cooling unit. In otherembodiments, the cooling units may placed in other locations, and in oneembodiment, one or more cooling units may be positioned to be closest toa rack or racks that generate the greatest heat in the modular datacenter.

Further, in embodiments of the present invention, the roof over the hotarea may include a number of fans that are controlled to exhaust airfrom the hot area in the event of a failure of an air conditioning unitin the modular data center, and/or when air temperature in the hot areaexceeds a predetermined limit or if air pressure in the hot area exceedsa predetermined limit.

In embodiments of the invention described above, racks of modular datacenters are described as being arranged in two rows. In otherembodiments, the racks can be arranged in other geometricalconfigurations. Further, on sides of a modular data center, one or moreracks can be used in addition to or in place of one or both side panels.

Still further embodiments are within the scope and spirit of theinvention. Referring to FIG. 4, a system 210 includes a power protectionunit 212, a power distribution unit (PDU) 214, a floor-mounted coolingsystem 215 that includes multiple cooling units 216, equipment racks218, and doors 220, 222. As used here, the devices 212, 214, 216, 218refer to functional equipment (as appropriate), mounting brackets,and/or enclosures/housings containing the brackets and equipment. Thus,the racks 218 as used here refer to mounting brackets (for mountingelectronic, heat-producing equipment) and/or to the housings thatcontain the mounting brackets and allow passage of gas through thehousings. The system 210 is configured with the devices 212, 214, 216,218 disposed in two displaced rows 224, 226 connected by the doors 220,222. Backs of the devices 212, 214, 216, 218 are disposed adjacent (andpossibly connected) to each other to form two sides of a hot region 228with the doors 220, 222 forming two other sides of the hot region 228.The doors 220, 222 may help control access to equipment in the racks218, e.g., by being locked to restrict access to the hot region 228.While the cooling units 216 are shown disposed adjacent to each otherwith an end unit disposed adjacent to the PDU 214, this is not requiredand other positions of the cooling units 216 relative to the otherdevices 212, 214, 218 are acceptable.

Although the system 210 is shown arranged in the two rows 224, 226connected by the doors 220, 222, other arrangements are acceptable. Forexample, the system 210 could be configured in triangular, circular, orrectangular/square arrangements, etc. Further, while two doors 220, 222are shown, other quantities of doors, e.g., one or three, etc. may beused. Additionally, panels that do not open may be used in place of anyor all (although preferably not all) of the doors. The system 210provides a laterally or horizontally restrictive environment definingthe hot region 228 and inhibiting gas from exiting laterally from thehot region 228 except through the cooling system 215.

The system 210 helps to contain heated air in the hot region 228 andisolate the heated air expelled from the racks 218 from cooled airprovided by the cooling system 215. The equipment in the racks 218 drawcool air from fronts 230, 232 of the racks 218 and expel heated air outbacks of the racks 218 into the hot region 228. The flow of gas throughthe equipment inhibits gas from flow from the hot region 228 through theracks 218 toward the fronts 230, 232. Further, the doors 220, 222 arethermally-insulating doors that help contain heat from the gas in thehot region 228. The devices 212, 214, 216, 218 and the doors 220, 222provide a top opening 229 allowing gas from the hot region 228 tovertically exit the hot region 228, e.g., by rising. The doors 220, 222are at least about as tall as the shortest of the devices 212, 214, 216,218 to help retain heated gas in the hot region 228. Preferably, thedevices 212, 214, 216, 218 and the doors 220, 222 are about the sameheight. The doors 220, 222 and the flow of gas through the racks 218help contain heated gas in the region 228 and isolate heated gas in theregion 228 from gas outside of the system 210. Isolating and containingthe heated gas helps inhibit heated gas from flowing horizontally andcombining with cooled gas provided by the cooling system 215. Devicessuch as the power protection unit 212 and the PDU 214 exhaust smallquantities of heated gas into the hot region 228.

The cooling system 215 is configured to draw heated gas from the hotregion 228, cool it, and provide cool gas to the exterior of the system210 near bottoms of the fronts 230, 232 of the racks 218. The system 215is powered through a voltage feed 240 and uses cold water or otherrefrigerant from a supply line 242 to cool the drawn-in air. The wateror other refrigerant, having been raised in temperature, leaves thesystem 215 via a return line 244 to be re-cooled. Preferably, thecooling units 216 are disposed and configured to draw in significantamounts of the heated air/gas from the hot region 228 before the heatedgas rises and exits the region 228. The heated gas, typically about 95°F., is cooled by the units 216 to about 72° F. and expelled out fronts234 of the units 216 near the fronts 230, 232 of the racks 218. If nocooling units 216 are disposed in the same row 224 or 226 with equipmentracks 218, naturally occurring convection effects cause cool gas fromone or more of the units 216 to flow to the fronts 232 of the racks 218in the other row 224, 226. Preferably the cooling units 216 provide coolgas near the floor (near bottoms of the racks 218) and in amounts suchthat most of the cool gas is drawn into the equipment racks 218. Theunits 216 can direct cool gas as desired using, e.g., fans, ducts,vents, vanes, pipes, etc. The units 216 cool the gas without significantlatent heat removal (dehumidifying cooling) and without introducingmoisture into the gas.

The cooling system 215 is a computer room air conditioner (CRAC)disposed in close proximity to heat-producing equipment in the equipmentracks 218. Locating the cooling system 215 close to the racks 218reduces and/or eliminates problems encountered by systems with CRACsdisplaced significantly far from the heat-producing equipment, inparticular problems getting cool air from the CRAC to the heat-producingequipment. For example, the cooling system 215 can use lower air/gasvelocity than displaced systems, reducing the pressure drop (fan coilCRAC pressure loss), and thus use lower fan power to propel the air/gas.

Embodiments of the system 210 may have similar dimensions to the datacenter 10 shown in FIG. 1. For example, with seven equipment racks 218the system 210 may have a length, including 36″ service clearance onboth ends, of 216″ and a width, including 36″ service clearance on bothsides, of 192″.

Embodiments of the system 210 may include features of the system 10 notspecifically mentioned with respect to the system 210. For example, thedoors 220, 222 can have windows configured and disposed for viewing byadults. Further, the system 210 can include a UPS connected, through thePDU 214, to provide power to devices in the system 210 to help ensureuninterrupted power for desired devices in the system 210. Otherfeatures may also be included in the system 210.

Referring to FIG. 5, with further reference to FIG. 4, the system 210 isconfigured to perform a process 250 of cooling equipment stored inenclosed racks using an infrastructure having independent power andcoolant supplies. The process 250 includes the stages shown, althoughthe process 250 may be altered, e.g., by having stages added, deleted,or moved relative to the stages shown.

At stage 252, power is supplied from the power distribution unit 214 tothe equipment racks 218. The equipment racks 218 may contain a varietyof electronic equipment that uses a consistent power supply to avoidsystem downtime. Power is supplied via the voltage feed 240 that isconnected to the power distribution unit 214, with a power protectionunit 212 preferably being disposed adjacent to the power distributionunit 214 and configured to ensure redundant power supply.

At stage 254, the racks 218 draw cool air from the surrounding roomthrough the front faces 230, 232 of the racks 218. There may, forexample, be an air distribution unit within the racks 218 and/or withinequipment contained in the racks 218 that draws the room air into theracks 218 and distributes the air throughout the racks 218 to coolcomponents contained in the racks 218. As the air passes through theracks 218, the air increases in temperature.

At stage 256, the racks 18 expel the air at an increased temperatureinto the hot region 228. The air is expelled out of the backside of theracks 218, e.g., through slots or vents in rear doors or directly intothe region 228 if the racks 218 do not have rear doors. Air isrestrained in the hot region 228 by the devices 212, 214, 216, 218, thedoors 220, 222, and the flow of air into the region 228, thus inhibitingmixing of the warm air with the surrounding ambient air.

At stage 258, the cooling units 216 draw the warm air from the hotregion 228. The cooling units 16 use the cold water from the cold watersupply 242 to cool the air from the hot region 228.

At stage 260, the cooled air is released from the cooling units 216 intothe surrounding room. The cool air is expelled from the units 216 anddirected to the fronts 230, 232 of the racks 218. The air in thesurrounding room is then drawn into the racks 218 once again, and thecycle continues. Preferably, the units 216 and the racks are configuredsuch that the units provide the cooled air and the racks 218 draw in thecool air such that much of the cooled air is drawn into the racks 218,e.g., to help reduce mixing of the cooled air and the heated air fromthe hot region 228.

Embodiments of the invention may provide one or more of the followingcapabilities. Mixing of exhaust air with cool air in a data center isreduced. Hot spots around groups of high power racks can be reduced bycontaining such high power racks in a modular data center as describedabove. The use of localized cooling allows air conditioning units in adata center, including within modular data centers, to operate moreefficiently and produce cool air at higher temperatures, therebynegating the need for humidifying systems. Temperature gradients may bereduced compared to prior systems. Equipment reliability can be improvedcompared to prior equipment/cooling arrangements. Cooling units canoperate with good efficiency and near their designed capacities.Equipment can be cooled using less energy than with previous systems.Cooling unit efficiency compared to prior systems can be increased, andcooling units that are smaller and/or have lower capacities than inprior systems can be used to provide similar cooling effects (e.g., tocool similar-sized regions). Standard building fire protection andlighting can be used for a data center. Existing data centers can beeasily retrofitted/upgraded in accordance with the invention. Physicalsecurity may be improved compared to prior systems.

Still further capabilities may be provided, such as sensible heat ratiosnear one may be achieved. The sensible heat ratio (SHR) is the sensiblecooling capacity QS divided by the total cooling capacity QT(SHR=QS/QT). The sensible and total cooling capacities in BTU are givenby:QS=(T ₁ −T ₂)·CFM·1.08QT=(H ₁ −H ₂)·CFM·4.45where T₁ is the temperature of gas entering the cooling unit 216, T₂ isthe temperature of gas exiting the cooling unit 216, H₁ is the enthalpyof gas entering the cooling unit 216, H₂ is the enthalpy of gas exitingthe cooling unit 216, 1.08 is a constant for standard air for convertingdelta temperature to BTU when multiplied by CFM, 4.45 is a constant forstandard air converting delta enthalpy to BTU when multiplied by CFM,and CFM is the amount of gas (entering and exiting, respectively, theunit 216) in cubic feet per minute. For example, for an incomingtemperature T₁ of 80° F. at 36% RH (relative humidity), an incomingenthalpy H₁ of 27.82 btu/lbmass, an exit temperature T₂ of 50° F. at 95%RH, and an exit enthalpy H₂ of 19.89 btu/lbmass, the SHR is about 0.92.

Having thus described at least one illustrative embodiment of theinvention, various alterations, modifications and improvements willreadily occur to those skilled in the art. Such alterations,modifications and improvements are intended to be within the scope andspirit of the invention. Accordingly, the foregoing description is byway of example only and is not intended as limiting. The invention'slimit is defined only in the following claims and the equivalentsthereto.

1. A modular data center for housing and cooling electronic equipment,the data center comprising: a plurality of housings, a first portion ofthe housings configured to hold heat-producing electronic equipment anda second portion of the housings configured to hold at least one coolingunit, each of the housings of the first portion having a front and aback and configured to hold the heat-producing electronic equipment suchthat gas is drawn into the equipment from fronts of the equipment,heated by the equipment to become heated gas, and expelled by theelectronic equipment through the backs of the housings; wherein thehousings are disposed and coupled to form a laterally-enclosedarrangement laterally enclosing a hot region and defining a top openingallowing gas to vertically exit the hot region; and wherein backs of thehousings of the first portion are disposed adjacent to the hot regionsuch that the heat-producing equipment, when mounted to the housings,will expel the heated gas into the hot region.
 2. The data center ofclaim 1 further comprising the at least one cooling unit, the at leastone cooling unit being configured to draw heated gas from the hot regioninto the at least one cooling unit, cool the heated gas to becomerelatively cool gas, and to expel the heated gas from the at least onecooling unit to a cool region that is separated from the hot region. 3.The data center of claim 2 wherein the at least one cooling unit isconfigured to direct the cool gas toward fronts of the first portion ofthe housings.
 4. The data center of claim 3 wherein the at least onecooling unit is configured to direct the cool gas toward bottom portionsof the fronts of the first portion of the housings.
 5. The data centerof claim 2 wherein the at least one cooling unit is configured to coolthe gas to, and expel the gas at, approximately 72° F.
 6. The datacenter of claim 2 further comprising an uninterruptible power supplycoupled to the at least one cooling unit and configured to providebackup power to the at least one cooling unit.